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| Titel |
Dynamic analysis of groundwater discharge and partial-area contribution to Pukemanga Stream, New Zealand |
| VerfasserIn |
V. J. Bidwell, R. Stenger, G. F. Barkle |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 12, no. 4 ; Nr. 12, no. 4 (2008-07-28), S.975-987 |
| Datensatznummer |
250010752
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| Publikation (Nr.) |
 copernicus.org/hess-12-975-2008.pdf |
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| Zusammenfassung |
| The proportion and origin of groundwater contribution to streamflow from
agricultural catchments is relevant to estimation of the effects of nitrate
leached from the soil on the quality of surface waters. This study addresses
the partitioning of streamflow contributions from near-surface runoff and
from groundwater, each with different contributing land area, on a steep
pastoral hillslope in a humid climate. The 3 ha headwater catchment of the
perennial Pukemanga Stream, in the North Island of New Zealand, was
instrumented for continuous observation of climatic data, streamflow and
groundwater level. The dynamics of groundwater levels and groundwater
contribution to streamflow were analysed by means of a one-parameter,
eigenvalue-eigenfunction description of a 1-D aquifer model. Model results
for seven years of daily data predict that 36–44% of the topographical
catchment contributes groundwater to the stream. The remaining groundwater
generated within the catchment contributes to streamflow outside the
catchment. Groundwater was calculated to be 58–83% of observed annual
streamflow from the topographical catchment. When the smaller groundwater
catchment is taken into account, the groundwater contribution to streamflow
is 78–93% on a unit area basis. Concurrent hourly data for streamflow and
groundwater levels at two sites indicate the dynamic behaviour of a local
groundwater system. Groundwater flow dynamics that support the perennial
nature of this headwater stream are consistent with the size of the
groundwater body, porosity of the subsurface material, and hydraulic
conductivity derived from partitioning of streamflow contributions. |
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